Coating of CoS on hybrid anode electrode with enhance performance in hybrid dye-sensitized solar cells

Abstract

Improvement of the power generation performance of dye-sensitized solar cells (DSSCs) remains a key task, as charge transfer and charge separation are efficiently achieved at the photoanode and between the polysulfide electrolyte interface and the counter-electrode. We synthesized the metal sulfides from dithiocarbamate complexes and used them to fabricate a new modified cell by passivating the photoanode electrode with CoS nanoparticles and SnS as photosensitizer in a two-step deposition approach. They were used as FTO-TiO2/CoS/SnS/HI-30/FTO-Pt, known as C-S-1, C-S-2 and C-S-3. SEM images show that the C-S-1 and C-S-2 are uniform, without cracks and have a dense surface morphology covering the surface area. Thus, confirming the successively passivation by CoS and sensitization of SnS, forming FTO-TiO2/CoS/SnS heterostructure. The η of 8.79% and 9.43% are much higher than that of C-S-2, with 0.23% affirm the roles of the Co, Sn and S ratio on both devices. The EIS Nyquist plot for the C-S-2 device shows a semicircle radius smaller than the C-S-1 and C-S-3, which indicates more efficient inhibition of electron/hole pairs and faster transportation of photogenerated charge carriers. The enhanced performance of both devices shows that the passivation of the electrodes ensures that maximum absorption is achieved through a higher absorption coefficient of SnS. Also, both devices reach a steady state within about 200–300 s and remain at the steady state current for a long duration for C-S-1 and C-S-3. The enhanced performance of both devices shows that the passivation of the electrodes ensures that maximum absorption is achieved through a higher absorption co-efficient of SnS.